September 17, 1886.] 



8CmNGB, 



251 



heard. One of those which was received with 

 most enthusiasm was that of Nadault de Buflfon, 

 a descendant of our great naturalist, an old man 

 already, and quite blind, but possessed with a 

 strong voice, a fine appearance, and very enthu- 

 siastic feelings. 



After this avalanche of speeches, which was cer- 

 tainly enough to fatigue one, M. Chevi-eul an- 

 swered some words in reply, and the delegations 

 defiled before him. The number of them was 

 very considerable, but he witnessed the whole 

 proceeding nevertheless. All saluted him with 

 utmost respect and demonstrations of great joy. 

 He was presented with a nosegay — I know not 

 by which delegation — that was a masterpiece of 

 art in the choice and distribution of colors. No 

 more delicate allusion could be made to the ven- 

 erable master's theory of complementary colors ; 

 and it was understood by the whole crowd, being 

 exemphfied in an unparalleled manner. 



The ceremony was over at four o'clock. There 

 were crowds of people around the monument, 

 awaiting the passage of the centenarian, and 

 progress was difficult and trying. However, all 

 went very well, and Chevreul was received by the 

 crowd with deafening applause. 



It is likely that our readers would have been 

 tired after all this ordeal : Chevreul was not. 

 The same evening he was present at a great ban- 

 quet given in the Hotel de ViUe, and he even 

 drank some champagne when his health was pro- 

 posed, — a somewhat superfluous motion, it seems. 

 During the night a torchlight procession paraded 

 the streets ; but this popular demonstration had 

 nothing iuteresting in it, and no savants were 

 concerned in this masquerade, which certainly 

 originated in the brains of some alderman desirous 

 of more votes at the next election. 



Upon the whole, Chevreul's centennial anni- 

 versary was celebrated as it ought to have been, 

 and as becomes, at the same time, a man of 

 high scientific standing, and a city which always 

 appreciates great thoughts and a noble life. 



H. DE Varigny. 



BURYING THE WIRES. 



The actual work of preparing subways or 

 underground conduits to receive the telegraph 

 and telephone wires, in this city, was begun on 

 Aug. 30. Numerous experiments and tests were 

 made, and many projected methods considered, 

 l)efore the commissioners having the matter in 

 charge decided upon a plan which seemed to 

 them satisfactory. The system finally selected 

 appears to fulfil all the requirements of the case, 

 and the work of 'burying the wires,' so long 



discussed by the daily papers, will now proceed as 

 rapidly as the conduits can be placed in position. 



The subway, as now being constructed in Sixth 

 Avenue, consists of a double row of conduit- 

 blocks, laid in a trench five or six feet deep, with 

 man-holes at every cross-street, for the insertion 

 of wires and making connections. Each block is 

 42 inches long, 17i inches deep, 13^ inches wide, 

 weighs about 450 pounds, and is pierced by twelve 

 2i-inch holes. The material of which the blocks 

 are made is a concrete composed of 80 per cent 

 clean, sharp sand, 191 per cent coal-tar pitch, and 

 i per cent oil and black oxide of manganese. 

 These are thoroughly worked together in a tank 

 at a high temperature. The mixture is then 

 forced into moulds of proper size and shape, sub- 

 jected to heavy pressure, and deposited to cool in 

 tanks of water. At a public test conducted by 

 Mr. Albert R. Ledoux, chemical expert to the 

 subway commission, the crusliing resistance of 

 this concrete was found to be 4,591 pounds to 



the square inch, and the crushing resistance of 

 a conduit section was 59,210 pounds. This con- 

 crete deteriorates and disintegrates in a few years 

 where exposed to great changes of temperatm-e, 

 so that it is not adapted for use in pavements, or 

 where exposed to the heat of the sun and the 

 action of snow and frost ; but the experience of 

 several years proves that it undergoes no appreci- 

 able change when used under ground. As a 

 material for sewer and drain pipe, etc., it has 

 been found satisfactory. 



The conduits are being laid in a manner that 

 ought to insure their stabihty. At the bottom of 

 the trench is laid a bed of cement concrete six 

 inches in thickness. This is allowed to harden, 

 after which the sections are placed in position, in 

 two rows, leaving a space of two inches between 

 the rows, to be afterwards filled with hydraulic 

 cement. The method adopted to insure the con- 

 tinuity of the * ducts,' or holes, through which the 

 wires will run, is simple but effectual. The holes 

 are movilded with a slight enlargement at the 



